6 Ways to Remove Carbon Pollution from the Atmosphere

By: Katie Lebling and Audrey Denvir

Since the Industrial Revolution, humans have emitted more than 2,000 gigatonnes of carbon dioxide into the atmosphere. (A gigatonne is one billion metric tons.)

This concentration of CO2 and other greenhouse gases in the air causes the climate change impacts we’re experiencing today, from forest fires to stifling heat waves and damaging sea level rise – and the global community is still emitting more each year. Unless we make serious changes, climate impacts will only continue to intensify.

The imperative for combating climate change is to curb emissions rapidly – for example, by ramping up renewable energy, boosting energy efficiency, halting deforestation and curbing super pollutants like hydrofluorocarbons (HFCs). The latest assessment of climate science from the Intergovernmental Panel on Climate Change (IPCC) tells us, however, that these efforts alone aren’t enough.

To keep global temperature rise to less than 1.5 degrees C (2.7 degrees F), which scientists say is necessary for preventing the worst impacts of climate change, we’ll need to not only reduce emissions but also remove and store some carbon that’s already in the atmosphere.

Carbon dioxide removal (or simply “carbon removal”) aims to help mitigate climate change by removing carbon dioxide pollution directly from the atmosphere. Carbon removal strategies include familiar approaches like growing trees as well as more novel technologies like direct air capture, which scrubs CO2 from the air after which it can be sequestered underground.

Carbon removal is different from carbon capture and storage (CCS), which captures emissions at the source – like from a power plant or a cement producer – and prevents those emissions from entering the atmosphere in the first place. Carbon capture is a form of emissions reduction rather than carbon removal.

The latest climate model scenarios show that in addition to substantial and rapid emissions reductions, large-scale carbon removal will be needed to keep temperature rise to 1.5 degrees C. The amount of carbon removal ultimately needed will depend on how quickly we reduce emissions in the near term as well as the magnitude and duration of any increase above 1.5 degrees C, known as overshoot. Estimates, including both natural and technological carbon removal approaches, range from 7 billion to 9 billion metric tons per year globally by 2050. For context, the United States emitted just over 6 billion metric tons of greenhouse gases in 2023. The faster the world reduces its emissions in the near term, the less it will have to rely on carbon removal. Conversely, as global emissions continue to rise, more carbon removal would be needed to meet global climate goals.

While enhancing natural carbon removal through reforestation and forest management has long been of interest, efforts to develop and deploy novel technologies and approaches have ramped up more recently. In less than a decade, carbon removal has grown from a niche concept to a well-accepted component of climate portfolios and has received billions of dollars of government funding and private investment.

This expansion was largely spurred by a 2018 report from the IPCC which concluded that hundreds of billions of tons of carbon removal will be needed by the end of the century to meet global climate goals. More recent IPCC reports from 2022 have reaffirmed this finding. The level of carbon removed today remains far below what we expect to need in the coming decades, indicating a need for investment in the public and private sectors to continue growing.

As investment and deployment increases, it is important to make sure carbon removal is deployed responsibly. This includes making sure it complements, rather than replaces, emissions reduction, minimizes negative impacts on people and ideally provides benefits, and uses resources sustainably, among other factors.

Carbon removal can take numerous forms, from new technologies to land management practices. The big question is whether these approaches can deliver carbon removal at the pace and scale needed in the coming decades.

Each carbon removal approach involves tradeoffs, including varying costs, resource needs (such as energy, land and water usage), benefits or negative impacts to people or the environment, and technology readiness, among others. Understanding the extent of these tradeoffs in different circumstances and investing in a portfolio of carbon removal approaches will be key to balancing them.

Here are six options for removing carbon from the atmosphere:

Plants remove carbon dioxide from the air naturally, and trees are especially good at storing CO2 removed from the atmosphere by photosynthesis. Expanding, restoring and managing tree cover to encourage more carbon uptake can leverage the power of photosynthesis, converting carbon dioxide in the air into carbon stored in wood and soils.

Some management approaches that can increase carbon removal by trees and forests include:

Earlier WRI research estimates that the theoretical carbon removal potential from forests and trees outside forests in the United States alone is more than half a gigatonne per year as of 2020, equivalent to all annual emissions from the U.S. agricultural sector. What’s more, approaches to remove CO2 through forests can be relatively inexpensive compared to other carbon removal options (generally less than $50 per metric ton of CO2) and yield cleaner water and air in the process.

One major challenge is ensuring that forest expansion in one area doesn’t come at the expense of forests somewhere else. For example, taking farmland out of production would reduce the supply of food. This could necessitate converting other forests to farmland – resulting in more greenhouse gas emissions – unless improvements in farm productivity could fill the gap. Similarly, not harvesting timber from one forest may result in overharvesting in another. These dynamics make restoring and managing existing forests, and adding trees to ecologically appropriate lands outside of farmland, especially important.

Continue reading here for the other five options for removing carbon from the atmosphere.

Katie Lebling – Senior Associate, Carbon Removal

Audrey Denvir – Research Associate II, U.S. Lands